Conventionally, multimedia such as video and audio has been delivered using analog delivery mediums such as NTSC (National Television System Committee) signals, and has been stored using analog storage mediums such as video cassette recorders. The analog signals typically contain uncompressed frames of video. Thus, a significant part of the electronic components in a display device are dedicated to analog receiving hardware, and if the display device has a digital output, electronic components are needed to convert the analog signal to a digital signal. With the advent of digital delivery mediums, such as ATSC (Advanced Television Systems Committee) signals, and of digital storage mediums and DVDs, multimedia can be delivered and stored using pure digital signals. Digital signals typically contain compressed frames of video.
Meanwhile, consumers and business have an increasing number of digital playback devices such as high-definition televisions, digital video recorders, MP3 players and the like. However, the digital playback devices are typically independent of each other. Furthermore, the digital playback devices are likely to use a digital format that is optimized for particular storage and playback capabilities. For example, a high-definition television can use a conventional high-definition signal, but a standard-definition television or a portable video player typically uses a digital signal with different characteristics. Differences in digital formats can include encoding, bit rate, resolution, and the like.
Due to differences in conventional playback devices, there are limits in the types of digital formats that can be input and output from the devices. In order to handle more digital formats, the complexity of related hardware increases exponentially. One reason for this is that the digital formats are typically decompressed in order to perform operations in the spatial domain to make use of legacy analog techniques which operate on decompressed video. Decompressed multimedia, especially video, requires bulky processing hardware to handle the high bandwidth for data transfers. Decompressed video also requires significant amounts of storage.
A particular need in digital media applications involves changing media from a first compression format into a second compression format. Such a need may arise, for example, when a digital media broadcast feed is in a format that is not compatible with a certain playback system. The need to change digital media formats is becoming increasingly pervasive as more digital broadcast, distribution, storage, processing, and playback systems are brought into use.
Traditional approaches involve decoding media from a first compression format to a complete uncompressed representation of the media and then encoding the uncompressed representation into a second compression format. Such a process has several major drawbacks. For example, it is computationally expensive. Encoding media streams, in particular, is a complicated task that requires significant processing resources to achieve in real-time. In addition, changing media formats through complete decompression requires additional bandwidth, as the uncompressed representation of the media typically requires more storage space than either the first media in the first compression format or media in the second compression format.
Therefore, there is a need for systems and methods to efficiently change media of a first compression format to media of a second compression format.